Historic structures provide a significant cultural value and in the case of the Seattle waterfront, link the maritime period around Seattle’s founding to the current tourist and commercial center of the city. In addition to contributing to the local heritage and historic fabric, existing buildings generally also contribute disproportionately to the energy consumption of our building stock. Pier 56 was constructed in 1900 over Elliott Bay as a timber structure and for much of its history was a base for nautical transportation. Today, the lower floor of the building houses several retail and restaurant tenants. The upper floor, approximately 30,000 square feet, is leased by the architecture firm Mithun, winner of the 2023 AIA Architecture Firm Award.

Mithun leased the space in 2000 and as part of a lease renewal in 2020, completed tenant improvements including air sealing. The goal of the air tightening measures was to reduce energy use and improve occupant comfort, which was a challenge for a vaulted exposed timber structure with no cooling and no perimeter heat distribution.

This session is a case study covering the pre-improvement multi-fan air barrier testing, diagnostics completed during testing to determine leak locations, remedial work completed during construction, and the final air barrier test. We will also include pre- and post-occupancy energy use comparison and occupant descriptions of comfort improvements.

1. Participants will be able to identify at least three locations of air leakage in a historic timber framed structure.
2. Participants will be able to establish a methodology for determining, designing, and confirming air tightening measures in existing buildings.
3. Participants will be able to evaluate the value of different air sealing measures on occupant comfort.
4. Participants will be able to understand the methods used to validate performance improvements associated with air sealing old buildings.